For a number of years a-amylase enzymes have been used for a variety of different purposes, the most important of which are starch liquefaction, textile desizing, starch modification in the paper and pulp industry, and for brewing and baking. A further use of .alpha.-amylases, which is becoming increasingly important is the removal of starchy stains during washing and dishwashing.
Examples of commercial .alpha.-amylase products are Termamyl.RTM., BAN.RTM. and Fungamyl.RTM., all available from Novo Nordisk A/S, Denmark. These and similar products from other commercial sources have an acidic to a neutral pH optimum, typically in the range of from pH 5 to pH 7.5, which means that they do not display optimal activity in detergent solutions owing to the alkaline character of the detergents.
It is an object of the present invention to provide novel .alpha.-amylases with improved performance in alkaline solutions, especially in alkaline detergent solutions.